{"product_id":"o2-oxygen-sensor-upstream-downstream-for-jaguar-xjr-2004-2005-4-2l-supercharged","title":"O2 Oxygen Sensor Upstream Downstream for Jaguar XJR (2004-2005) 4.2L Supercharged","description":"\u003ch2 style=\"font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;\"\u003eDirect-Fit O2 Sensor Kit for 2004-2005 Jaguar XJR (X350)\u003c\/h2\u003e\u003cp\u003e\u003cstrong\u003eWhat it Does:\u003c\/strong\u003e This 4-piece upstream and downstream oxygen sensor kit monitors exhaust air-fuel ratios on the 2004-2005 Jaguar XJR (\u003cstrong\u003eX350\u003c\/strong\u003e) \u003cstrong\u003eAJ34S 4.2L Supercharged V8\u003c\/strong\u003e to maintain closed-loop fueling and emissions compliance.\u003c\/p\u003e\u003ch3\u003eThe Stock Jaguar XJR Sensor Failure\u003c\/h3\u003e\u003cp\u003eSustained boost from the factory supercharger subjects the \u003cstrong\u003eX350\u003c\/strong\u003e chassis and \u003cstrong\u003eAJ34S 4.2L Supercharged V8\u003c\/strong\u003e to extreme exhaust temperatures that degrade OEM zirconia sensing elements. Carbon fouling, thermal shock, and internal heater circuit burnout slow voltage switching over time. Aged sensors matching \u003cstrong\u003e234-9030\u003c\/strong\u003e and \u003cstrong\u003e234-4798\u003c\/strong\u003e skew closed-loop fuel trims, triggering \u003cstrong\u003eP0130\u003c\/strong\u003e, \u003cstrong\u003eP0135\u003c\/strong\u003e, and \u003cstrong\u003eP0171\/P0174\u003c\/strong\u003e codes while masking true catalytic converter efficiency.\u003c\/p\u003e\u003ch4\u003eCommon Symptoms of a Failing OEM Oxygen Sensor\u003c\/h4\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eCheck Engine Light \/ DTCs:\u003c\/strong\u003e Triggers heater and slow-response codes like \u003cstrong\u003eP0135\u003c\/strong\u003e, \u003cstrong\u003eP0155\u003c\/strong\u003e, or \u003cstrong\u003eP0420\/P0430\u003c\/strong\u003e.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFuel Trim Drift:\u003c\/strong\u003e Erratic voltage forces rich open-loop fueling under supercharged boost.\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFailed Emissions:\u003c\/strong\u003e Delayed closed-loop control increases exhaust pollutants and cuts fuel economy.\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eThe Direct-Fit 4-Piece Oxygen Sensor Solution\u003c\/h3\u003e\u003cp\u003eReplacing all four sensors simultaneously restores balanced bank-to-bank air-fuel feedback across both cylinder banks of the \u003cstrong\u003eAJ34S 4.2L Supercharged V8\u003c\/strong\u003e. Each direct-fit sensor utilizes a fast-light-off internal heater, double-layered stainless protective shield, and zirconia ceramic element built for high-heat forced-induction exhaust on the \u003cstrong\u003eX350\u003c\/strong\u003e. Factory-length leads and OEM-style weatherproof connectors directly replace \u003cstrong\u003e234-9030\u003c\/strong\u003e upstream and \u003cstrong\u003e234-4798\u003c\/strong\u003e downstream units with zero splicing.\u003c\/p\u003e\u003ch3\u003eWhat's Included\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e2x Upstream Oxygen Sensors\u003c\/li\u003e\n\u003cli\u003e2x Downstream Oxygen Sensors\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eTechnical Specifications\u003c\/h3\u003e\u003cdiv style=\"overflow-x: auto; margin-bottom: 20px;\"\u003e\u003ctable width=\"100%\" style=\"border-collapse: collapse; border: 1px solid #e0e0e0; font-size: 14px; min-width: 300px;\"\u003e\n\u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eFitment\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e2004-2005 Jaguar XJR\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eEngine \/ Chassis\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003eAJ34S 4.2L Supercharged V8 \/ X350\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eEmissions \u0026amp; Substrate\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003eHeated Zirconia Ceramic \/ 4-Sensor Set\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eInstallation Type\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003eDirect Bolt-On OEM Replacement (No Splicing)\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr style=\"background-color: #f9f9f9;\"\u003e\n\u003cth style=\"padding:10px; text-align: left; border: 1px solid #e0e0e0;\"\u003eReplaces OEM Part #\u003c\/th\u003e\n\u003ctd style=\"padding:10px; border: 1px solid #e0e0e0;\"\u003e234-9030, 234-4798\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/table\u003e\u003c\/div\u003e\u003ch3\u003eCompatibility\u003c\/h3\u003e\u003cul\u003e\u003cli\u003e2004-2005 Jaguar XJR 4.2L Supercharged (4-Piece Set)\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions \u0026amp; Fitment Warnings\u003c\/h3\u003e\u003ch4\u003eDoes this fit the X350 XJR?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes.\u003c\/strong\u003e Fits 2004-2005 Jaguar XJR models with the \u003cstrong\u003eAJ34S 4.2L Supercharged V8\u003c\/strong\u003e. \u003cstrong\u003eXJ8 4.2L non-supercharged models require a separate listing; confirm engine before ordering.\u003c\/strong\u003e\u003c\/p\u003e\u003ch4\u003eWill this clear P0130, P0135, or P0171\/P0174 codes?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes, if sensors are faulty.\u003c\/strong\u003e New \u003cstrong\u003e234-9030\u003c\/strong\u003e and \u003cstrong\u003e234-4798\u003c\/strong\u003e units restore heater resistance and signal speed after clearing DTCs.\u003c\/p\u003e\u003ch4\u003eAre connectors plug-and-play?\u003c\/h4\u003e\u003cp\u003e\u003cstrong\u003eYes.\u003c\/strong\u003e Pre-wired OEM-style connectors thread directly into factory bungs with no cutting or splicing required.\u003c\/p\u003e\u003ch3\u003eThe Jaguar Precision Standard\u003c\/h3\u003e\u003cp\u003eBuilt for European emissions accuracy and ECU precision, this 4-sensor kit keeps your \u003cstrong\u003eX350\u003c\/strong\u003e running clean and CEL-free. Maintain factory closed-loop fuel control.\u003c\/p\u003e","brand":"VelocityMax","offers":[{"title":"Default Title","offer_id":68119471161592,"sku":"DS-EZQ6B19LH","price":114.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0800\/1290\/2648\/files\/o2-oxygen-sensor-upstream-downstream-for-jaguar-xjr-2004-2005-4-2l-supercharged-1.jpg?v=1794722800","url":"https:\/\/performancechiptuning.com\/products\/o2-oxygen-sensor-upstream-downstream-for-jaguar-xjr-2004-2005-4-2l-supercharged","provider":"Performance Chip Tuning","version":"1.0","type":"link"}